A wireless communication device, when powered on or when returning from an out of service condition, can perform a scan of radio frequencies to determine a set of potential wireless base transceiver stations (or their equivalent) with which to attempt to associate and/or connect. The wireless communication device can operate using one or more different radio access technologies in accordance with one or more different wireless communication protocols. Each radio access technology can use a set of radio frequencies available in one or more different radio frequency bands. The wireless communication device can attempt to locate a base transceiver station that uses a particular preferred radio access technology, e.g., an evolved Node B (eNB) of a wireless network that operates in accordance with a Long Term Evolution (LTE) wireless communication protocol. As the LTE wireless communication protocols, as published by the Third Generation Partnership Project (3GPP) standardization group, provide for a substantial number of different radio frequency (RF) channel bands, each RF channel band including numerous different radio frequencies, an exhaustive search for an available radio frequency can take a significant amount of time. Thus, an intelligent search that reduces the amount of time required to scan for radio frequencies in a radio frequency band can be desired.
The wireless communication device can seek to identify a radio frequency that uses a particular radio access technology. The wireless communication device can perform a scan of radio frequencies within a channel band (a contiguous range of radio frequencies) and determine the frequencies on which a base station may be transmitting. For example, in an LTE wireless network, the wireless communication device can perform a frequency scan within a frequency channel band and determine a set of Evolved Universal Terrestrial Radio Access Absolute Radio Frequency Channel Numbers (EARFCNs) on which an evolved Node B (eNB) may be transmitting. In general, the number of EARFCNs in a given frequency channel band can be large, and typically the wireless communication device seeks to limit the number of acquisitions it performs to reduce a time required to associate with and/or connect to a cell in a wireless network.
Presently, wireless communication devices limit the number of acquisition attempts by scanning for a static number, n, of frequencies determined to have the strongest detected power during a frequency band scan. This criterion can guarantee that the frequency band scan time will not take more than n*T for attempting a single acquisition, where T corresponds to a time to search a given radio frequency. However, using a static number to limit the number of frequencies on which to attempt acquisition may not be optimal in many circumstances. For example, in the case of an empty radio frequency channel band, with no frequencies available with which to connect or none that use one or more particular or preferred radio access technologies, such as a frequency band without any LTE signals, attempting acquisition using a fixed static number of frequencies can take a relatively long time, only to ultimately result in an unsuccessful acquisition attempt. On the other hand, if the radio frequency channel band is highly loaded, such as when the wireless communication device can receive signals from multiple different overlapping cells of different wireless network, then it can be desirable to spend more time to attempt acquisition on a range of frequencies, as it is likely that some of the frequencies may be transmitted in accordance with a preferred radio access technology, e.g., an LTE signal, while other frequencies may include signals from wireless networks that use less preferred or non-preferred radio access technologies. Thus, for example, if it is desired to scan for an LTE system, it can be desirable to spend more time inspecting numerous frequencies from “strong” systems in a “crowded” radio frequency channel band to prune out the non-LTE systems, e.g., by increasing the number of frequencies scanned, such that any available cells of a preferred radio access technology, e.g., LTE systems, are not overlooked.